Achalasia
• Achalasia is a condition in which the lower
esophageal sphincter fails to relax during
swallowing
• Food swallowed into the esophagus then fails
to pass from the esophagus into the stomach
• Damage in the neural network of the
myenteric plexus in the lower two thirds of
the esophagus.
• The musculature of the lower esophagus
remains spastically contracted and the
myenteric plexus has lost its ability to transmit
a signal to cause receptive relaxation of the
gastroesophageal sphincter as food
approaches this sphincter during swallowing
• Stretching the lower end of the esophagus by
means of a balloon inflated on the end of a
swallowed esophageal tube
• Antispasmotic drugs (drugs that relax smooth
muscle) can also be helpful.
Gastritis (Inflammation of the Gastric
mucosa)
• The inflammation may be
• Superficial
• Deep
•
•
•
•
It can be due to
Irritant substances in the ingested food
Stomach’s own peptic secretions
Bacterial infection
Gastric Atrophy
• In many people who have chronic gastritis the
mucosa gradually becomes more and more
atrophic until little or no gastric gland digestive
secretion remains
• Some develop autoimmunity against the gastric
mucosa leading eventually to gastric atrophy
• Loss of the stomach secretions in gastric atrophy
leads to achlorhydria and occasionally to
pernicious anemia.
Achlorhydria
• Stomach fails to secrete hydrochloric acid
Pernicious Anemia in Gastric Atrophy
• Normal gastric secretions contain a
glycoprotein called intrinsic factor secreted by
the same parietal cells that secrete
hydrochloric acid.
• Intrinsic factor must be present for adequate
absorption of vitamin B from the ileum
12
Peptic Ulcer
• A peptic ulcer is an excoriated area of stomach
or intestinal mucosa caused principally by the
digestive action of gastric juice or upper small
intestinal secretions
Marginal Ulcer
• Type of peptic ulcer formed at the site
wherever a surgical opening such as a
gastrojejunostomy has been made between
the stomach and the jejunum of the small
intestine
• The usual cause of peptic ulceration is an
imbalance between the rate of secretion of
gastric juice and the degree of protection
• Bacterial Infection by Helicobacter pylori
Breaks Down the Gastroduodenal Mucosal
Barrier
• psychic disturbances may cause peptic ulceration.
• Other factors that predispose to ulcers include
(1)smoking presumably because of increased nervous
stimulation of the stomach secretory glands;
(2) Alcohol because it tends to break down the mucosal
barrier
(3) aspirin and other non-steroidal anti-inflammatory
drugs that also have a strong tendency for breaking
down this barrier
• Use of antibiotics along with other agents to
kill infectious bacteria
• Administration of an acid-suppressant drugs
Diarrhea
• Diarrhea results from rapid movement of fecal
matter through the large intestine
• Infectious Diarrhea
• Psychogenic Diarrhea
• Ulcerative colitis
Vomiting
• Vomiting is the means by which the upper
gastrointestinal tract rids itself of its contents
when almost any part of the upper tract
becomes excessively irritated, overdistended
or even over excitable
• Excessive distention or irritation of the
duodenum provides a strong stimulus for
vomiting
• The sensory signals that initiate vomiting originate mainly
from the pharynx, esophagus, stomach and upper portions
of the small intestines.
• These sensory signals are transmitted by both vagal and
sympathetic afferent nerve fibers to widely distributed
nuclei in the brain stem that all together are called the
vomiting center
• Motor impulses that cause the actual vomiting are
transmitted from the vomiting center by way of the 5th,
7th, 9th, 10th, 12th cranial nerves to the upper
gastrointestinal tract, through vagal and sympathetic
nerves to the lower tract and through spinal nerves to the
diaphragm and abdominal muscles.
• Antiperistalsis begins to occur often many
minutes before vomiting appears
Vomiting Act
• deep breath
• raising of the hyoid bone and larynx to pull the upper
esophageal sphincter open
• closing of the glottis to prevent vomitus flow into the lungs,
and
• lifting of the soft palate to close the posterior nares.
• Next comes a strong downward contraction of the diaphragm
along with simultaneous contraction of all the abdominal wall
muscles. This squeezes the stomach between the diaphragm
and the abdominal muscles building the intragastric pressure
to a high level. Finally the lower esophageal sphincter relaxes
completely allowing expulsion of the gastric contents
upward through the esophagus.
Chemoreceptor Trigger Zone
• “Chemoreceptor Trigger Zone” in the Brain
Medulla for Initiation of Vomiting by
Drugs(morphine) or by Motion Sickness.